Ok, it is a 2002 2.7l AWD santa fe. Sometimes the transmission wont engage and the engine revs but the vehicle does not move. Sometimes if you fiddle with it for a while it will start working and you can move the vehicle then it fails again. There is a buzzing sound that, from what I can make out, is coming from right behind the transmission pan. It doesn't make this noise all the time. The fluid looks full and clean, if anything maybe over full. There are no check engine codes. Im debating getting rid of the car but don't want to if I can fix it myself. Ideas?